Question: $-2lmn + 8m - 3n + 9 = -5m + 3n - 7$ Solve for $l$.
Explanation: Combine constant terms on the right. $-2lmn + 8m - 3n + {9} = -5m + 3n - {7}$ $-2lmn + 8m - 3n = -5m + 3n - {16}$ Combine $n$ terms on the right. $-2lmn + 8m - {3n} = -5m + {3n} - 16$ $-2lmn + 8m = -5m + {6n} - 16$ Combine $m$ terms on the right. $-2lmn + {8m} = -{5m} + 6n - 16$ $-2lmn = -{13m} + 6n - 16$ Isolate $l$ $-{2}l{mn} = -13m + 6n - 16$ $l = \dfrac{ -13m + 6n - 16 }{ -{2mn} }$ Swap the signs so the denominator isn't negative. $l = \dfrac{ {13}m - {6}n + {16} }{ {2mn} }$